Bolster damping arrangement for railway car trucks



July 28, 1959 c. w. WULFF 2,896,550

BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8. 1956 I 12 Sheets-Sheet l m H [II] I 'I M 1' 152 2/622 207' .CaZ k lfizlff v C. W. WU LFF July 28, 1959 BOLSTER DAMPINC ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 1956 12 Sheets-Sheet 2 July 28 1959 c. w. WULFF BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS -Filed Feb. a, 1956 12 Sheets-Sheet 3 July 28, 1959 c. w. WULFF 2,896,550

BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 195a 12 Sheets-Sheet 4 g J0 .232 man 20: gal JKJ/aZ/f C. W. WULF BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 1956 12 Sheets-Sheet 6 C l ZKJ/a/Zff fimwflh M July 28, 1959 c. w. WULFF 2,896,550

BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 1956 12 Sheets-Sheet 7 ma num" MIIJHAIII JH AWW IWM' l 122 K frwezzar UQZ 2%M27f July 28, 1959 C. W. WU LFF BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS 12 Sheets-Sheet 8 Filed Feb. 8, 1956 Z ah "l July28, 1959 c. w. WULFF 2,896,550

BOLSTEZR DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS 7 Filed Feb. 8, 1956 r 12 Sheets-Sheet 9 ,Z za Y k I N frzueni'or O a/Z )K2fiaiff July 28,1959 c. w. WULFF 2,896,550

BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 1956 12 Sheets-Sheet 10 July 28,1959

'C. W. WULFF Y BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Filed Feb. 8, 1956 12 Sheets-Sheet 11 WW 2 WQTW Q %%L @MN QQN 152M? ni'ar I I IIII IIIIA/4A Zfii United States Patent 9 BOLSTER DAMPING ARRANGEMENT FOR RAILWAY CAR TRUCKS Cal W. Wulif, Chicago, 111., assignor to Holland Company, Chicago, 111., a corporation of Illinois Application February 8, 1956, Serial No. 564,294

9 Claims. (Cl. 105197) This invention relates to a bolster damping arrangement for accurately controlling the movement of a bolster relative to its supporting side frame, and more particularly, it is concerned with a novel housing arrangement that is provided in the bolster to accommodate the spring loaded components of the frictiondamping apparatus in a simpler and safer manner and direct these components into frictional engagement with the opposed vertical surfaces of the side frame columns flanking the bolster.

Present bolster damping arrangements in which the friction components are carried in the bolster are notoriously inflexible as respects correlating the control spring forces with the capacity of the car on which the equipment is mounted. Similarly there is no convenient arrangement for compensating for wear at the friction surfaces and for decreased spring characteristics resulting from normal operation. In addition, present bolster damping arrangements involve friction systems which are maintained in a loaded condition during installation and removal operations by means of some form of retaining element and such arrangements hold out an unnecessary danger to the personnel involved.

The principal object of the present invention is to overcome the above noted disadvantages of the prior art bolster damping arrangements.

Briefly this is accomplished by providing elongated internal housings extending from the bolster side wall to the center rib to accommodate the components of the friction system in free position entirely within the confines of the internal housing. The control springs are preferably of the large diameter long travel type. The rear ends of the internal housing are slotted adjacent the center rib of the bolster to accommodate a suitable mechanism for adjustably loading the control springs in order to correlate their loading with car capacity and/ or to allow for metal loss from friction wear and loss of spring strength occurring in normal operation of the friction system. Preferably the internal housings are cast integrally with the normal bolster arrangement in order to maximize the length of these housings.

The extra large internal housings resulting from the integral construction employed actually result in a friction system having improved operating characteristics. The improved system results in part from the fact that large diameter long travel springs offer a more accurate longitudinal aligning action and provide a better distribution of the bearing pressure applied to the friction block and in part, results from the fact that a larger and deeper friction block may be employed to improve the guiding and aligning action imposed on the block by the adjacent portions of the internal housing.

The fact that the components of the friction system may be assembled in free position within the friction housings avoids the necessity of such non-functional miscellaneous parts as retainer keys and of course eliminates the operations involved in applying and removing such miscellaneous parts. Thus the free position arrangement of the present invention eliminates pre-assembly operations, simplifies truck assembly procedures, and insures L setting and removing the loading bars;

handling safety during installation and breakdown since no spring loaded parts are involved.

a The present invention finds greatest advantage whenembodied in axially loaded friction block systems (a system in which the axis of the control spring is normal to the plane of the cooperating friction faces) and in this connection the friction block may be modified to include a rearwardly extending guide portion for cooperation with guide housing portions formed on the bolster.

Still other features of the present invention permit the control spring and/or the friction block to be applied after the truck has been assembled and to be removed without disassembling or disturbing the truck bolster in any way.

Other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Fig. 1 is a fragmentary side elevational view of a freight car truck of the spring plankless type equipped with a bolster damping arrangement according to this invention, and with parts thereof broken away to better illustrate the construction of the friction housing and friction apparatus;

Fig. 2 is an enlarged sectional view taken in the vertical plane of line 2-2 of Fig. 1; 4

Fig. 3 is an enlarged fragmentary plan View partly in section and taken in the horizontal planes of line 3-3 of Fig. 1;

Fig. 4 is a side elevational view partly in section illustrating the construction of the internal housing and friction apparatus and is taken in the vertical planes of line 44 of Fig. 3;

Figs. 5 and 6 correspond respectively to Figs. 3 and 4 but illustrate the relationship of the parts of the friction apparatus when in their free or unloaded condition within the internal housing;

Fig. 7 is a transverse sectional view through the fric tion block and adjacent housing portions and is taken in the vertical plane of line 7-7 of Fig. 4;

Figs. 8 and 9 are side elevational and rear views, re spectively, of the friction block employed in the embodi ment shown in Figs. 1 through 7. Figs. 10 and 11 are generally similar to Figs. 2 and 4, respectively, and illustrate a modified arrangement of the invention whereinportions of the internal housing and the friction block are formed with cooperating rearward extensions that guide and align these parts during operation;

Figs. 12 through 18 illustrate another embodiment of the invention and correspond respectively to Figs. 1 through 7; V

Fig. 19 is a perspective view better illustrating parts of the friction system of the embodiment of Figs. 12 through 18;

Figs. 20 and 2.1 are plan sectional and side views of a modified form of the embodiment of Figs. 12 through 19, Fig. 21 being taken in the vertical planes of line 21--21 of Fig. 20;

Fig. 22 is generally similar to Fig. 4 and illustrates a modified control spring loading arrangement;

Fig. 23 is a perspective view of the loading clip of Fig. 22;

Fig. 24 is a side view of a modified form of loading bar;

Figs. 25 and 26 are fragmentary side views illustrating two different arrangements for applying shims to the friction apparatus in order to adjust the control spring load- Fig. 27 is a sectional view of an impact tool for in- Fig. 28 is a plan sectional view through the internal housings illustrating a modified arrangement for loading the control spring;

Fig. 29 is a sectional view taken in the vertical plane of line 29-29 of Fig. 28;

Fig. 30 is a plan sectional view through the internal housings illustrating still another modified arrangement for loading the control spring;

Fig. 31 is similar to Fig. 30 but showing the control spring loading mechanism in various different positions; and

Figs. 32 and 33 are fragmentary sectional views taken in the vertical planes of lines 3232 and 3333, respectively, of Fig. 30.

Referring now to the general arrangement of Fig. 1, there is shown a conventional side frame 30 of a freight car truck. The side frame includes a compression member 31, a tension member 32, and spaced side columns 34 that define a bolster opening 35 within which the truck bolster generally designated 36 is located. The bolster is supported on a plurality of springs 37 that rest upon a spring seat 38 in the bottom of the bolster opening. It should be understood that the invention is fully as applicable to a freight car truck of the spring plank type.

The general arrangement of the bolster 36 is of familiar construction and comprises top and bottom walls 40 and 41, respectively, side walls 4 2 having the usual outer and inner guide flanges 43 cooperating with the side frame columns 34 to maintain proper bolster positioning, and a transversely extending center rib portion 44.

A pair of internal housings, each generally designated 46, are provided in back to back relationship at each end of the bolster and they receive the friction producing apparatus which cooperates with the opposed vertical faces of the side frame columns 34. Towards this end the side frame columns are provided with Wear plates 47 which preferably are welded thereon to provide pposed vertically disposed flat friction faces.

As best seen in Figs. 2, 3, 4, and 7, the internal housings 46 are preferably cast integrally with the bolster 36 as this arrangement permits most efficient use of the available space but the invention need notbe limited to such a construction. Each internal housing consists of two main parts, a spring barrel portion generally designated at 48 and a somewhat larger friction block portion generally designated at 49. The spring barrel housings are rigid with and extend outwardly or longitudinally from the opposite sides of the center rib 44 to merge at their outer ends with the rearmost portions of the friction block housings 49.

As best seen in Figs. 2 and 7, the spring barrel 48 is cylindrical in cross section and the friction block housing 49 is generally rectangular.

The friction block housing is defined by laterally extending rear wall portions 50, longitudinally extending side walls 51, and by portions of the top and bottom walls 40 and 41, respectively, of the bolster. 'Thus, the friction block housing forms a generally block-shaped chamber, the longitudinally extending interior walls of which also serve to guide and align the friction block 53.

The friction block '53 as best shown in Figs. 8 and 9 is provided with a relatively wide and flat front friction face '54 and includes a circular recess 55 extending forwardly from its rear face 56 to form a spring seat for the outer end of a control spring. The inner end of the control spring 57 telescopes over a circular boss to engage an annular surface portion of a movable spring seat 53.

Both from the standpoint of structural strength and also to accommodate large size parts for the friction apparatus, it is preferred that the internal housings be cast integrally with the bolster. Thus the control spring may 2,896,550 7 j v i W,

be of the long travel, large diameter type in order to apply a more effective longitudinal aligning action and to better distribute the bearing pressures which are imposed upon the friction block. A large size friction block exhibits a more effective aligning and guiding action and also offers a relatively wide surface area in frictional contact with the wear plate 47.

An important feature of the invention resides in the fact that the internal housing extends the entire distance between the center rib 44 and the side Wall 42 of the bolster and this super-elongated housing is readily capable of accommodating the parts of the friction producing apparatus in their free position. This arrangement is illustrated in Figs. 5 and 6 wherein the control spring 57 is shown extended to its full free height and nevertheless the entire assemblage comprising the movable spring seat 58, the control spring 57, and the friction block 53 is positioned entirely within the internal housing.

This free position arrangement of the friction parts requires a supplementary means for loading the control spring to its desired operating point. According to the preferred arrangement, the movable spring seat 58 is provided with a laterally extending rectangular slot 60 in its rear face, and as best seen in Figs. 3 and 4, a generally channel-shaped loading bar 62 cooperates with the slot 60 and reacts between the center rib 44 and the movable seat 58 to load the control spring appropriately and urge the friction block 53 into contact with the wear plate 47. For this purpose the spring barrel 48 is provided with rectangularly shaped lateral access slots 63 extending forwardly from adjacent the center rib 44 of the bolster.

The parts of the friction producing apparatus are moved forwardly in the internal housing to the maximum possible extent to provide substantial clearance and the loading bar 62 is formed with a sharp leading edge as indicated at 65 to facilitate its insertion into the slot 60. The intermediate portion of the loading bar is of constant thickness and thus constitutes a firmly positioned spacer element for the movable spring seat. The parallel load bearing and transmitting surfaces of the loading bar 62 preclude the possibility of the loading bar shaking loose during operation and maintain the spring seat normal to the control spring axis. It will be apparent that wedges of different thicknesses may be employed in order to pro vide any desired degree of control spring loading, and this arrangement permits the control spring loadings to be correlated with the car capacity in order to provide optimum performance. Furthermore, since normal operation of the system slowly wears away the metal friction surfaces and tends to decrease the spring strength, it may be desirable to use a wedge of increased thickness in order to restore the control spring loading to its original value. All such adjustments may be readily carried out simply by interchanging the loading bars 62 and without disturbing the truck assembly.

Alternative means for adjusting the control spring loading such as a single loading bar having a plurality of suitable steps or circular or annular shims are described hereinafter.

An important feature of the free position arrangement of the parts is the fact that the operations of assembling and disassembling the parts of the freight car truck are simplified and made less hazardousv In the assembly of the truck, the friction parts are first inserted into the bolster internal housings in the position indicated in Figs. 5 and 6 and then the bolster is mounted in the truck side frame in the usual manner. The parts of the friction system are accommodated entirely within the internal housings and do not in any way interfere with the assembly operation, but in addition to this, there are no spring loaded parts to contend with while mounting the bolster in the side frame. No miscellaneous non-functional parts, such as retainer keys, need be handled and stored.

The embodiment of Figs. 1 to 9 is of the axially loaded friction block type and exerts a well-known three-way control over movements of the bolster relative to the truck side frame. The up and down vertical movements and lateral movements of the bolster relative to the truck side frame are all subjected to equal and constant stabilize ing forces by the axially loaded damping system and the tendency for the bolster to rotate about its center bearing or become out of square is resisted by the direct axial loading of the control springs.

Another advantage of the present arrangement is the fact that the friction block 53 is formed with a plurality of relatively large flat side faces which cooperate with the walls of the internal housing to guide and align the friction block and insure that the friction damping system is accurately loaded.

In Figs. and 11, a modification of the present invention is shown wherein the friction block 53 is provided with a pair of integral rearwardly extending guiding and aligning bars 70 of circular cross section and the internal housing is formed to include a pair of integral cylindrical chambers '71 to receive these guide bars. The other parts of the bolster damping arrangement of Figs. 10 and 11 are generally similar and are therefore designated by corresponding numbers. The particular cross sectional configuration of the guide bars and guide chambers is substantially a matter of choice; however, the presence of these additional guiding and aligning elements in con nection with the structure previously described materially enhances the performance of the system and insures that the characteristics of a truly axially loaded system will be realized.

It will be apparent that the guiding and aligning facilities could be reversed by casting suitable chambers in the rear face of the friction block and forming corresponding projections on the friction block housing. Such an arrangement conserves material and simplifies the coring and casting operation.

Another embodiment of the invention is shown in Figs. 12 through 19 wherein a free position friction damping arrangement is again employed in combination with a suitable loading bar but which in addition allows insertion and removal of the control spring for inspection and replacement without disturbing the bolster mounting. Identical reference characters are employed for designating the familiar parts of the truck side frame, bolster, and suspension system shown in Fig. 12 and these parts need not be redescribed. The modified internal housings of this embodiment, however, are designated generally by reference character 146.

Referring now to Figs. 13, 14, 15, and 18, and particularly to the fragmentary perspective view of the internal housing and friction block of Fig. 19, it may be seen that the internal housings are again cast integrally with the familiar parts of the bolster and comprise two main parts; a spring barrel portion generally designated as 148, and a friction block portion generally designated as 149. Each spring barrel is rigid with and extends in an outward or longitudinal direction from the bolster center rib 44 to merge with the rear end of the friction block housing 149.

As best seen in Figs. 13, 18, and 19, the spring barrel is generally U-shaped in cross section and consists of top and bottom ledge portions 152 and 153, respectively, that are connected by a semi-circular barrel portion 154. As shown the top and bottom ledge portions 152 and 153 are tangent extensions of the semi-circular barrel portion 154, and as will become clear, serve as convenient glides for the application and removal of the control spring.

The friction block housing 149 is generally similar to that of the previous embodiment in that it defines a generally block-shaped chamber having a rectangular cross section somewhat larger than the spring barrel and in that the inner surfaces of the walls are relatively wide and flat to provide an accurate guiding and aligning ac- 6 tion for the friction block. Thus the friction block hous ing is defined by the top and bottom bolster walls 40 and 41, longitudinally directed inboard and outboard side wall portions 156 and 157, respectively, and laterally directed rear wall portions 158. It will be noted that portions of the outboard side wall 157 and of the rear wall are left open in order to facilitate the insertion and removal of the control spring and this will be made more clear presently.

The friction block is generally designated as 160 and is similar to the friction block of the previous embodiment in that it has a relatively large flat front friction face 161 for cooperation with wear plate 47 and is provided with a circular recess 162 extending forwardly from its rear face 163 to provide a spring seat for the outer end of the control spring. However, the friction block 160 is modified in that its rear face 163 is provided with a laterally extending rectangular notch of lesser depth than the recess 162 and merging therewith to define a generally U-shaped lateral access slot for the front end of the control spring. The rectangular notch is defined by the top and bottom horizontal lips 165 and 166.

The general arrangement of parts is such that when the friction block 166 is mounted in its housing, the :U-shaped recess in the block is congruent with the U-shaped chamber defined by the spring barrel 148 and is aligned laterally with the open portion of the outboard side wall 157. The parts of the friction system are shown mounted in the internal housing in free position in Figs. 16 and 17. The movable spring seat 58 and control spring 57 may be similar in construction to the corresponding parts of the embodiment of Figs. 1 to 9. The specific control spring design, however, will be somewhat different since the embodiment of Figs. 12 to 19 allows for a somewhat larger diameter spring but requires that the spring be of a slightly smaller free height in order that it may be inserted and removed without disassembling the bolster.

The parts of the friction system are assembled in the following manner:

Before the bolster is positioned Within the side frame,

the friction blocks 160 are inserted in their housings to the full extent so that they do not project beyond the bolster side walls and inhibit the installation of the bolster within the bolster opening; after the bolster is installed and lowered onto the bolster springs, the control spring 57 and movable spring seat 58 are: assembled as indicated in phantom in Fig. 16 and inserted laterally into the U-shaped spring barrel. This operation is facilitated by the \horizontal ledges 152 and 153 which exert a desirable guiding action. When the control spring andspring seat assembly has been advanced to its fullest extent laterally, it is aligned with the recess 162 and may be moved away from the center rib 44 and into this recess prior to the insertion of the loading bar 62 that is generally similar to the loading bar described in connection with the first embodiment.

It will be noted from Figs. 16 and 17 that not only are the parts readily accommodated in free position but there is in fact a considerable amount of play in the in ternal housing. Therefore, by comparison with the previous embodiment, it may be seen that thecontrol spring has a somewhat shorter free height. 'Thus, it is recog ni'zed that the spring design will be somewhat diiferent and therefore the loading bar 62 may correspondingly with the spring 7 located a substantial distance outboard so that they do not limit the clearances required for the insertion and remove]. of the control spring and spring seat assembly.

Since maintenance expenses for bolster damping sys terns which require compelte truck disassembly in order to inspect and/or replace parts are unduly high, it is most advantageous that the control spring be removable without disassembling the truck. Experience has shown that the control spring is one of the most frequently replaced components in the friction damping system. However, according to a further embodiment shown in Figs. 20 and 21, it becomes possible to also install and remove the friction block itself without disassembling the truck.

The modified embodiment of Figs. 20 and 21 is gen erally similar to the embodiment shown in Figs. 12 through 19 and the identical parts are numbered identically whereas the modified parts also include a prime. It will be noted that the spring barrel 148 which is of U-shaped cross section is considerably shortened and the friction block housing 14-9 is correspondingly lengthened; however, the outboard wall 157 of the internal housing still terminates short and thus, between the rear wall 158' of the friction block housing and the rearmost eX- tremity of the outboard wall 157 there is provided a space sufficient to permit the friction block 160 to be inserted and removed through the end of the bolster, and this is best illustrated in Fig. 20.

Various modifications of the control spring loading arrangement are also contemplated within the scope of the invention and are illustrated in Figs. 22 to 33.

From a marketing standpoint it is desirable to minimize the material costs associated with the loading mechanismand one convenient means for accomplishing this is shown in Figs. 22 and 23. It will be seen that this modification relates to the embodiment of Figs. 1 to 9 which involves a spring barrel that is substantially closed. The lateral access slot 63 in the spring barrel is modified to include auxiliary top and bottom slots 170 which communicate with the main access slot and which serve as supporting shoulders for a load bearing clip 171 that is adapted to be inserted behind the movable spring seat 53 in order to maintain the control spring in its loaded condition. It will be noted that the movable spring seat is formed with spaced apart parallel notches 172 of semicylindrioal form that seat on the clip and prevent relative movement between the clip and the spring seat.

As shown in the right hand portion of Fig. 22 a loading bar '62 of conventional form is first inserted through the lateral access slots 63] in order to bias the movable spring seat beyond the auxiliary [recesses and afford adequate clearance for the insertion of the load bearing clip 171. The clip is of a generally U-shaped construction and has its outer end turned at an angle in order to clear the outer end of the loading bar. The clip may be of /8 inch round bar stock suitably treated to withstand the control spring pressures to which it will be subjected.

After the clip is in place, the loading bar is removed and the parts assume the position shown in the left hand portion of Fig. 22. it will be apparent that only a single loading bar is required to service an entire fleet of cars and since the U-shaped clips are considerably less expensive than the loading bars, this arrangement offers important economies.

As stated previously, loading bars of various thicknesses may be employed to appropriately regulate the control spring loading and. to make adjustments for metal loss due to friction. Fig. 24 illustrates a stepped loading bar 181? having a plurality of-constant thickness portio-ns. Such .an arrangement not only decreases the number of loading bars required but permits additional increments of spring bias to be applied merely by urging the loading bar 181) further inwardly until its next thickness plateau becomes operatively engaged between themovable spring seat and the bolster center rib.

Alternatively, however, various degrees of control spring loading can be provided by employing one or more shims of suitable thickness. Accordingly, in Fig. 25 a disc-like shim 132 is shown located between the movable spring seat 58 and the bolster center rib 44. Preferably the thickness of the shim is equal to theamount of metal loss occurring on the friction block and wear plate so that the shim exactly compensates for this metal loss and restores the damping characteristics of the friction system to their original values. It will be noted that since the shim thickness is correlated with the metal loss thickness that the parts of the friction apparatus are still accommodated entirely within the internal housing even when in free position.

Another convenient shim arrangement is shown in Fig. 26 wherein the shim 183 is in the form of an annular ring and is telescoped over the boss of the movable spring seat 53. While the shims are shown in connection with an open barrel embodiment they are equally as applicable to the closed barrel embodiment.

Fig. 25 also illustrates a modified spring seat and loading bar arrangement that readily accommodates bolster tipping about a horizontal axis such as occurs during train braking operations. As shown, the loading bar 62 is formed with a horizontally extending arcuate projection 184 of cylindrical form and the spring seat 58 is formed with a corresponding semi-cylindrical recess to permit relative rotation therebetween.

To facilitate their removal the loading bars 62 are formed with an eye 186 of suitable size adjacent their outer ends. An impact tool for this purpose is shown in Fig. 27 and consists of an elongated rod like member formed at one end with a hook 189 adapted to engagc within the eye 186 provided by the loading bar and provided at its opposite end with a U-shaped gripping element 1% adapted to snugly grip the outer end of the loading bar in order to deliver impacts thereto for urging the loading bar inwardly when it is applied to the friction producing apparatus. To deliver the impacts, the impact tool is provided with rigid stops 191 adjacent each end, and a cylindrical mass 192 is telescoped over the rod 1% for sliding movement between the stops 191. The mass 192. is formed such that it may readily be gripped by a persons hand and urged with a swift hard motion into contact with the appropriate stop 191. This impact tool greatly simplifies the procedure of inserting and removing the loading bars.

While it is preferred to employ these wedge-like loading bars having constant thickness load transmitting portions for biasing the control springs, the present invention need not be limited specifically to such arrangements. For instance, in Figs. 28 and 29, an adjustable screw threaded arrangement may be employed for actuating the movable spring seat and this screw threaded arrangement is shown applied to the closed barrel embodiment of Figs. 1 to 9. Briefly, the mechanism consists of a threaded rod 193 that passes through and is rigidly anchored to the center rib 44 of the bolster and that receives at each end in adjustable relationship a threaded nut 194 having flat faced sides for engagement with any suitable wrench, and an annular spring seat ring 195. if desired, suitable anti-friction means such as a ball bearing arrangement may be provided between the engaging faces of the spring seat ring 195 and the threaded nut 194 to facilitate relative sliding movement therebetwcen such as is occasioned when the spring loading is varied. A lateral access slot 1% of suitable size is provided in the spring barrel 4% to provide operating clearance for the wrench. This screw threaded arrangement provides pinpoint control of the control spring loading but it is not as stable and reliable as the loading bar arrangements.

In Figs. 30 to 33 still another arrangement for adjust- Aim ably loading the control spring is shown and this arrangement is shown in connection with the embodiment employing a spring barrel of U-shaped cross section. Briefly, it consists of a bell crank lever having an inner arm 200 pivotally connected to a trapezoidal-shaped member 201 by a pin 202. The member 201 is slidable laterally within a trapezoidal-shaped recess 203 formed in the movable spring seat 58'. The bell crank is pivoted to the bolster center rib 44 by means of a suitable pin 205 that is mounted between a pair of vertically spaced ears 206 that are rigidly anchored on the bolster center rib in any suitable manner. The outer arm 208 of the bell crank is apertured to receive a threaded rod 209 on which a suitable nut 210 is adjustably mounted for locking the spring biasing mechanism in any desired location.

In Fig. 30 the friction producing apparatus is shown in its fully loaded condition whereas in Fig. 31 on the left it is shown in an intermediate loading condition and on the right it is shown in its fully released condition.

It should be understood that the description of the preferred form of the invention is for the purpose of complying with Section 112, Title 35, of the U.S. Code and that the appended claims should be construed as broadly as the prior art will permit.

I claim:

1. In a railway car truck including a side frame having spaced columns providing opposed vertical friction faces, and a bolster having one end thereof resiliently supported between said columns, said bolster end having side walls facing said columns and having top and bottom walls and internal walls rigidly interconnecting said top and bottom walls to form opposed internal housings, with said housings defining oppositely directed chambers opening outwardly through the side walls of said bolster, said internal walls including vertical rib structure rigidly interconnected with said top and bottom bolster walls and dividing said chambers, with each chamber also opening laterally through the end of said bolster, a frictionproducing apparatus for each chamber and each including a movable spring seat, a control spring, and a friction block successively outwardly arranged within each chamber, each chamber accommodating its friction-producing apparatus with the control spring thereof in free expanded position during the installation of said apparatus in said chamber; and loading means within said bolster and movable therewith and interposed between each of said spring seats and said vertical n'b structure, said loading means being actuatable through the end of said bolster for positioning said seats lengthwise in said chambers to load said blocks against said vertical friction faces through said control springs.

2. The arrangement of claim 1 wherein a single center rib comprises said vertical rib structure and provides a rear wall common to and integrally merging with the internal side walls of each of said housings.

3. In a railway car truck of the type including a bolster having side, top and bottom walls, said bolster having each of its ends resiliently supported for vertical movement between side frame columns that flank the bolster opening with a friction-producing apparatus incorporated in each bolster end for cooperative engagement with a vertical friction surface provided on the adjacent side frame column; the improvement wherein each bolster end has internal walls rigidly interconnecting said top and bottom bolster walls to form a housing Within said bolster, with said housing defininga chamber that opens outwardly through the side wall of said bolster, said chamber also opening laterally through the end of said bolster, said internal walls including a fixed rear wall for said housing, friction-producing apparatus for said chamber and including a movable spring seat, a control spring and a friction block successively outwardly arranged Within said chamber, said chamber accommodating said apparatus with the control spring thereof in free expanded position during the installation of said apparatus in said chamber, and loading means within said bolster and movable therewith and interposed between said spring seat and said rear wall, said loading means being actuatable through the end of said bolster for po 'tioning said seat lengthwise in said chamber to load said block against said vertical friction surface through said control spring.

4. The. arrangement of claim 3 wherein said loading means is a bar that is insertable and removable through the end of the bolster while the friction-producing apparatus is in operative position therein, said bar being positioned between said rear wall and said movable spring seat for establishing a predetermined spacing between said spring seat and said rear wall.

5. The arrangement of claim 4 wherein said movable spring seat has a recess across the inner face thereof, said recess being complemental to and defining a nest for 10- cating and locking interengagement between said seat and said bar.

6. The arrangement of claim 3 wherein the internal walls that form the portion of said housing that extends in lengthwise flanking relation to the portion of said chamber that is occupied by said control spring and said movable spring seat defines a cross section of generally U-shaped configuration such that said chamber opens laterally through the end of said bolster throughout the length of the portion thereof that is occupied by said control spring and said movable spring seat to accommodate insertion and removal of said control spring and said movable spring seat while said bolster is in place within said side frame columns.

7. The arrangement of claim 6 wherein said housing has a transversely enlarged portion adjacent the outer end thereof for receiving said friction block, with said friction block having a rear face formed with a recess to provide a seat for the outer end of said control spring, the rearmost end of said recess opening laterally towards the end of said bolster to facilitate removal of said control spring.

8. The arrangement of claim 3 wherein said housing, throughout substantially its entire length and height, opens laterally towards the adjacent end of the bolster and has an inner portion for said movable spring seat and control spring and an enlarged outer portion for said friction block, with said outer portion being of sufiicient dimension in a direction lengthwise of said housing to accommodate insertion and removal of said friction block through the the end of the bolster while said bolster is in place between said side frame columns.

9. The arrangement of claim 3 wherein the internal walls flanking the length of said chamber include upper and lower pairs of abutment shoulders at spaced points about said chamber and said loading means is of rod-like form and is insertable through said housing outwardly of said abutment shoulders to react between the rear face of said movable spring seat and said abutment shoulders for holding said movable spring seat in predetermined, spaced relation from said rear wall.

References Cited in the file of this patent UNITED STATES PATENTS Quinn Oct. 2, 1951 

